• 한국지반신소재학회논문집
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• 제19권1호
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• pp.35-44
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• 2020

연약지반 개량 공법 중 심층혼합공법에 대한 설계 기법으로는 복합지반으로 해석하는 방법과 말뚝지반으로 해석하는 방법이 있다. 그러나 이러한 해석에 대한 비교 연구는 부족한 실정으로 설계 시 해석 기준을 명확하게 정의 내리는 것에 어려움이 있다. 본 연구에서는 2차원 및 3차원 해석을 통해 성토 높이와 연약지반의 심도, 보강구간의 치환율을 변화시키며 각 조건별로 복합지반과 말뚝지반을 가정하여 해석하였다. 그 결과 최저 개량 심도는 3차원 해석에 비해 2차원 해석 결과가 6.85~9.08% 더 깊은 결과를 도출하였다. 또한 말뚝지반 해석의 경우 복합지반 해석에 비해 개량 심도는 12.22~14.45% 더 깊은 것을 확인하였다. 이 결과를 통하여 보다 정확한 설계를 위해서는 2차원 해석보다는 3차원 해석을 실시해야 하고, 경제적인 설계를 위해서는 복합지반으로 해석해야 하며, 안정적인 설계를 위해서는 말뚝지반 해석을 실시해야 된다고 판단된다.

• 대한토목학회논문집
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• 제43권5호
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• pp.651-657
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• 2023

국내외 철도사업에서 철도의 신규 건설과 더불어 기존선의 개량을 통한 증속, 고속화 사업도 큰 비중을 차지고 있다. 특히 해외의 개발도상국은 경제수준을 고려할 때 고속철도의 건설은 막대한 규모의 예산소요와 수요를 고려할 때 한계가 있어, 기존 철도의 선형개량을 통한 증속사업이 실현가능성이 높은 것으로 판단하고 있다. 본 연구에서는 선형개량을 통향 기존선의 증속사업의 효율적 기획과 분석을 위하여, 기존에 신규 철도 건설사업 분석에 활용되고 있는 지능형 철도선형계획 프로그램(ei-Rail)에 선형개량사업 분석 기능을 추가할 수 있는 방법론을 개발하였다. 수치지도 또는 기존의 위성사진 자료를 기반의 베이스 맵에 기존의 철도선형을 입력하고, 목표속도등 선형개량사업의 목표를 입력하면, 사업의 비용과 도면, 증속효과 분석 결과 등을 자동적으로 제시함으로써, 철도선형개량 사업의 기획과 분석을 효율적으로 수행할 수 있는 도구로 활용될 수 있도록 하였다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2009년 춘계학술대회논문집
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• pp.57-65
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• 2009

An efficient and high-fidelity design approach for wing-body shape optimization is presented. Depending on the size of design space and the number of design of variable, aerodynamic shape optimization process is carried out via different optimization strategies at each design stage. In the first stage, global optimization techniques are applied to planform design with a few geometric design variables. In the second stage, local optimization techniques are used for wing surface design with a lot of design variables to maintain a sufficient design space with a high DOF (Degree of Freedom) geometric change. For global optimization, Kriging method in conjunction with Genetic Algorithm (GA) is used. Asearching algorithm of EI (Expected Improvement) points is introduced to enhance the quality of global optimization for the wing-planform design. For local optimization, a discrete adjoint method is adopted. By the successive combination of global and local optimization techniques, drag minimization is performed for a multi-body aircraft configuration while maintaining the baseline lift and the wing weight at the same time. Through the design process, performances of the test models are remarkably improved in comparison with the single stage design approach. The performance of the proposed design framework including wing planform design variables can be efficiently evaluated by the drag decomposition method, which can examine the improvement of various drag components, such as induced drag, wave drag, viscous drag and profile drag.

• 한국기계가공학회지
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• 제17권2호
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• pp.37-46
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• 2018

Present research is to evaluate and improve the sealing performance of the duct cap assembly for the ice dispensers through structural analysis. The nonlinear contact problems to check the sealing performance were analyzed using ANSYS software. The results of the analyses related to the sealing performance: the displacement distribution, the contact condition between the cap-silicon and the case, and the pressure distribution on the contact surface, were examined and discussed. Based on the results of the existing design of the duct cap assembly, two cases of the design modifications to improve the sealing performance were introduced. By examining the results of the two cases, a final design improvement plan was proposed and analyzed. It is shown that the sealing performance of the proposed final design is much more favorable than the existing design. The method of structural analysis and design improvement of the duct cap assembly presented in this paper will help improve the sealing performance of the ice dispenser duct caps.

• 항공우주시스템공학회지
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• 제17권4호
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• pp.87-94
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• 2023

본 논문은 항공기의 성능개량에 필수 수반되는 신규 및 변경 장비 장착부에 기체구조물 개조 및 장착설계를 수행한 연구이다. 항공기 외부에 장착되는 대표적인 성능개량 장비로는 안테나, 레이더, 전자광학/적외선 표적지시장치(EO/IR) 및 자체방어체계 장비 등이 있으며, 운용을 위해서 기본항공기의 구조보강, 개조 및 장착설계가 수행된다. 항공기 내부에는 사용자 운용 요구도에 맞게 콘솔과 랙 구조물이 개조 또는 추가된다. 또한 성능개량을 위해 교체 및 추가되는 장비의 장착설계와 이에 따른 내부 냉각을 위한 환경제어계통 구성품 개조가 수반된다. 성능개량 항공기의 구조건전성, 운용성 및 정비성이 확보된 기체구조물의 상세설계로 감항 적합성이 검증된 엔지니어링 과정과 사례를 제시하였다.

• Journal of Welding and Joining
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• 제24권2호
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• pp.42-47
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• 2006

While it is known that the weld toe grinding method may give 3.4 times of fatigue strength improvement, this improvement may significantly vary according to weld bead shapes and loading modes. Although tremendous interest have been given in improving fatigue strength improvement for ship structures, quantitative results are yet in need. In this context, a series of fatigue tests is carried out for a type of test specimen that are typically found in ship structures. Weld burr grinding is carried out using a electric grinder in order to remove surface defects and improve the weld bead profile. The test results are compared with the same type of test specimen without applying the fatigue improvement technique in order to obtain a quantitative measure of the fatigue strength improvement. On the other hand, both hot spot stress and structural stress methods are employed to compare the effectiveness of the two methods in evaluating the fatigue strength improvement of welded structures.

• 한국디자인학회:학술대회논문집
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• 한국디자인학회 2003년도 봄 학술발표대회논문집
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• pp.148-149
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• 2003

• 한국주거학회논문집
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• 제14권2호
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• pp.1-7
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• 2003

The purpose of this study is to develop the urban design guidelines in detached housing areas for the improvement and management of residential townscape. Through a detail examination and analysis of the urban design guidelines and landscape regulations of U.S.A, Japan, and Korea to be applied to detached housing area for residential townscape, the urban design guidelines in detached housing area was derived. Urban design guidelines are composed of building guidelines, landscape guidelines, street guidelines, and sign guidelines. The municipality have to make regulations in detached housing area for the improvement and management of residential townscape based on this urban design guidelines.

• International Journal of Aeronautical and Space Sciences
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• 제18권4호
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• pp.641-650
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• 2017

In order to include the design capability for a compound rotorcraft in a helicopter conceptual design and optimization framework, relevant further improvement was planned and conducted. Previously, a certain conceptual design optimization framework was developed by the present authors to design a modern rotorcraft with single main and tail rotor. The previously developed framework was further improved to expand its capability for a compound rotorcraft. Specifically, its power estimation algorithm was upgraded by using a comprehensive rotorcraft analysis program, CAMRAD II. The presently improved conceptual design and optimization framework was validated using data of the XH-59A aircraft.

• 한국BIM학회 논문집
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• 제5권4호
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• pp.37-46
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• 2015

In a construction project, collaboration amongst the project participants is a critical factor for high-quality results and successful completion of the project. Owing to the advance of information technologies, web-based systems have become more common in the construction industry, but research and development has been made for only limited areas. For organized and systematic collaboration in various fields, collaboration systems have to be developed in a holistic manner based on diverse needs from the whole construction industry. This study aims to investigate the current status of web-based collaboration systems from structural engineers' perspectives and propose an improvement plan. For a systematic analysis of selected cases, we apply a classification of three developmental stages depending on interoperability and organizational levels: structural design and analysis, collaborative design, and integrated design management. Thereafter, the characteristics of each stage are extracted and comparatively analyzed. Lastly, three functional factors were proposed for the improvement of web-based collaboration systems for structural design.